Ultramicrotome with means for adjusting the level of the liquid in the collecting vessel of the microtome



United States Patent Inventor Appl. No.

Filed Patented Assignee Priority ULTRAMICROTOME WITH MEANS FOR ADJUSTINGTHE LEVEL OF THE LIQUID IN THE COLLECTING VESSEL OF THE MICROTOME 13Claims, 7 Drawing Figs.

U.S. Cl. 83/167, 8 3/9 1 5.5

[51] Int. Cl G0ln 1/06 [50] Field ofSearch 83/167, 170,171, 651, 915.5

References Cited UNITED STATES PATENTS 3,225,639 12/1965 MartinelliPrimary Examinerwilliam S. Lawson Attorney-Michael S. Striker PatentedNov. 17, 1970 3,540,335

Sheet 1 of4 I INVENTOR 5 HEM/11477! 8 27 E ATTORNEY Patehted Nov. 11,1970 3,540,335

Sheet 2 3 (Prior/4r! INVENTOR H :44 n u m 5 1 rr;

ATTORNEY Patented Nov. 17,- 1970 3,5405335 Sheet 3 of4 mvsmoa H unum6/77:

BY 071.?100/ 16m!!!- ATTORNEY BACKGROUND OF THE INVENTION The presentinvention relates to ultramicrotomes, and more specifically to means foradjusting the level of the liquid in a collecting vessel fixed to thecutting knife of the microtome to one side of the cutting edge thereof.

As known in the art, cutting knives of ultramicrotomes are provided withsmall collecting vessels fixed to the cutting knife of the microtome toone side of the cutting edge of the knife, and such a collecting vesselis filled with liquid having a level flush with the upper edge of thecutting knife so that thin tissue sections cut by the knife may becollected on the upper surface of the liquid in the collecting vessel.The level of the liquid in the collecting vessel has to be adjusted, torreasons which will be explained later on in detail, in a very exactmanner so that the liquid vessel is in one plane with the upper edge ofthe cutting knife. Since the volume of such a collecting vessel isnecessarily very small, in the order of l emf, the exact adjustment ofthe liquid level in the collecting vessel is connected with considerabledifficulties.

It is one object of the present invention to provide means, which can beoperated in an efficient manner and without requiring any specialskills, for changing the amount of liquid in the collecting vessel.

It is a further object of the present invention to provide such meansfor adjusting the level of the liquid in the collecting vessel of amicrotome which are releasably connected to the cutting knife of themicrotome and which can be operated from a place spaced from the cuttingknife.

It is a further object of the present invention to provide for adjustingmeans for adjusting the level of the liquid in the collecting vessel ofa microtome which are constructed of relatively few and simple parts soas to be produceable at reasonable cost and so as to stand up properlyunder extended use.

SUMMARY OF THE INVENTION With these objects in view, the presentinvention comprises, in combination with an ultramicrotome having acutting knife with an upper cutting edge and a collecting vessel fixedto the cutting knife to one side of the cutting edge and adapted to befilled with liquid up to the cutting edge ofthe knife for collectingsections cut by the ultramicrotome, means for changing the amount ofliquid in the collecting vessel and for adjusting the level of theliquid in the vessel and including a tubular member extending from aboveinto the vessel and having a lower open end for the passage of liquidinto and out from the collecting vessel and being located at anelevation below that of the cutting edge of the knife so as to extendinto the liquid in the vessel when the latter is filled with liquid upto the cutting edge of the knife.

Support means, preferably, support the tubular member adjustable in atleast two directions relative to the cutting edge.

Preferably, the support means for adjustably supporting the tubularmember are mounted on mounting means which adjustably mount the cuttingknife on a support so that the support means and the tubular membermounted thereon will follow any adjustment of the position of thecutting knife.

It is further preferred to connect the support means supporting thetubular member releasably to the mounting means.

which carry the cutting knife so that before any necessary exchange 'ofthe cutting knife the support means may be removed from the mountingmeans of the cutting knife so as not to hamper any necessary exchange ofthe cutting knife.

The other end of the tubular member is preferably connected by aflexible tubing to the outlet end of a resiliently compressible liquidcontainer with which means cooperate for gradually compressing thecontainer so as to transfer liquid from the latter through the flexibletubing and the tubular member into the collecting vessel.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEFDESCRIPTION OF THE DRAWING FIGS. 1 and 2 are partially sectionedside views respectively schematically illustrating the cutting knife ofan ultramicrotome, the collecting vessel fixed to the cutting knife, andother elements of the ultramicrotome cooperating with the aforementionedelements;

FIG. 3 is a side view schematically illustrating an arrangementaccording to the prior art for adjusting the liquid level in thecollecting vessel of the microtome;

FIG. 4 is a schematic, partially sectioned, perspective view of anarrangement according to the present invention for adjusting the liquidlevel of the collecting vessel of a microtome;

FIG. 5 is a partially sectioned schematic side view and illustratingpart of the arrangement shown in FIG. 4;

FIG. 6 is a sectioned side view illustrating part of another embodimentaccording to the present invention; and

FIG. 7 is a partially sectioned front view of a portion of thearrangement shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 schematic-allyillustrate the general arrangement of a microtome provided with acollecting vessel on the cutting knife of the microtome. As shown inFIG. I the microtome may include a cutting knife I of substantiallytriangular cross section which may be formed from glass, and acollecting vessel the wall of which is formed by a thin strip of plasticmaterial 2 connected at the bottom edge thereof to the cutting knife Iin a sealed manner by a small mass of wax 3 or the like. The thus formedcollecting vessel is arranged to one side of the upper cutting edge ofthe cutting knife 1 and the collecting vessel is filled with a suitableliquid, for instance distilled water, so that the level of the liquid inthe collecting vessel is in one horizontal plane with the upper cuttingedge of the knife. Inthis way, thin tissue sections 6 cut from the block4 during reciprocation of the latter along a path 5 may float away onthe upper surface ofthe liquid in the collecting vessel from the uppercutting edge of the knife so that the sections 6 may be picked up bycarrier strips or nets from the upper surface of the liquid in thecollecting vessel.

An exact adjustment of the level of the liquid in the collect- 'ingvessel is for various reasons very important. If the upper surface ofthe liquid in the collecting vessel is convex, as shown at 7 in FIG. 2,then microvibrations will be created in the sections 6 cutoff from theblock 4, and such microvibration will hinder an electrone opticalexamination of the sections. On the other hand, a concave upper liquidsurface. as indicated at 8 in FIG. 2, will quickly cause withdrawal ofliquid from the upper edge of the cutting knife I so that the sectionswill not properly slide any longer on the dry cutting edge but will bepushed together and not be usable any longer. A further reason forexactly adjusting the upper surface of the liquid in the collectingvessel is that the thickness of the cuttissue sections has to beestimated according to interference colors. For this purpose it is knownto provide on ultramicrotomes a source of light, preferably in the formof a fluorescent tube 9, as shown in FIG. 1, arranged in such a mannerthat the light emanating therefrom will be reflected by the planarhorizontal upper liquid surface in the collecting vessel directly intothe objective pair 10 of a stereomicroscope indicated in FIG. I. Theinterference phenomena which permit on the basis of brightness and colordifferences an estimation of the thickness of the cuts can be observedonly from the objective pair 10.

The adjustment of the upper level of the liquid in the collecting vesselhas up to now been done mainly by dropwise adding or sucking off waterfrom the collecting vessel by means of a burette or by means of asyringe, which method has however various disadvantages, Persons who arenot very dexterous will encounter considerable difficulties to exactlyadjust the small volume of liquid in the collecting vessel, which isusually in the order of about 1 cm.", in such a manner that the uppersurface of the liquid will be located in one horizontal plane with theupper edge of the cutting knife. Since during use of the ultramicrotomethe position of the liquid level in the collecting vessel continuouslychanges due to removal of liquid from the collecting vessel duringfishing of the cut sections 6 therefrom, as well as due to e\ aporationof the liquid, small leaks in the collecting vessel and othercircumstances, it is necessary to continuously adjust the liquid levelin the collecting vessel. Even a person highly skilled in thismanipulation will spend a considerable time for adjusting the liquidlevel. Manipulation in the region of the cutting edge of the cuttingknife 1 will, in addition, produce a thermal effect on the instrumentwhich will detrimentally affect the further cutting operation.Furthermore, the upper surface of the liquid is in most cases due tosmall irregularities in the wall of the collecting vessel and on thecutting edge of the knife not perfectly plane so that only a limitedarea of the upper surface will satisfy the above-mentioned, reflectionrequirements. In other areas it is hardly possible to recognize the cutsections and in no case it is possible to judge the thickness andquality thereof. In this case it is necessary in order to properlyobserve the cut section to move the latter on the upper surface or toadjust the position of the upper surface of the liquid in the collectingvessel. Both manipulations may lead to a loss of some of the cutsections.

A perfect arrangement for adjusting the level of the liquid in acollecting vessel of the aforementioned kind has therefore to satisfythe following conditions:

The arrangement has to be'independent from the skill of the operator,i.e., it has to be operable in an extremely simple manner. Thearrangement has also to permit adjustment of the liquid level withoutmanipulation in the region of the cutting edge of the knife, that is byremote control. In addition the arrangement has to assure an exactdosing of the liquid addition or an exact dosing of removal of liquid sothat the upper level of the liquid may be located in one horizontalplane including the upper edge of the knife so as to provide a perfectreflection of the image of the cut sections into the objective pair 10.

For this purpose an arrangement as schematically illustrated in FIG. 3has already been suggested in which a collecting vessel formed by asheet metal member 11 cemented to the glass cutting knife 1 was providedand in which a small tube 12 extended through an opening in the sheetmetal member 11 and was carried thereby. It was also suggested to fastensuch a tube connection to the metal frame of diamond cutting knives. Thetube 12 has been connected by a hose 13 to means for supplying liquid tothe tube, for instance a syringe 14 the piston 15 of which was movablein axial direction by a screw arrangement 16, 17 connected thereto andturnable by a knob 18 at the outer end of the screw so as to move thepiston 15 in axial direction. While the arrangement shown in FIG. 3theoretically satisfies the above-mentioned conditions, this arrangementdid not work out satisfactorily in practice, since cementing of thesheet metal member 11 carrying the tube 12 onto the cutting knife hasbeen considerably more difficult than the forming of a collecting vesselby a plastic strip and since the mounting of such an arrangement on theframe of a diamond knife was connected with the risk of damaging thecutting edge of the diamond knife.

The arrangement according to the present invention differs basicallyfrom the known arrangement shown in FIG. 3. In the arrangement accordingto the present invention the collecting vessel is formed from a plasticstrip in the same manner as shown in FIGS. 1 and 2, but the tube forfeeding liquid in and out of the collecting vessel is not carried by thewall of the collecting vessel, but the tube extends from above into thecollecting vessel so that the lower open end of the tube is below thenormal level of the liquid in the collecting vessel. Accord ing to thepresent invention the tube is supported by support means independentfrom the wall of the collecting vessel and the tube support means arepreferably connected to the mounting means which carry the cutting knifeso as to be adjustable together with the latter. However, the supportmeans which support the tube are constructed in such a manner so as topermit adjustment of the position of the tube with respect to thecutting knife.

The arrangement according to the present invention is shown in anonlimiting manner in FIGS. 4-7.

Referring now to these FIGS., and especially to FIGS. 4 and 5, it willbe seen that the arrangement according to the present invention includesa cutting knife I of substantially triangular cross section having anupper cutting edge which is mounted on mounting means 19 ofa crosssection as best shown in FIG. 5, movable on the mounting means insubstantially horizontal direction in a known manner, not forming partof the present invention, by the knob 19a shown in FIG. 4, and themounting means 19 are in turn mounted in a slot of a support or block 20angularly adjustable about a horizontal axis in a known manner by meansof the knob 20a so that the angle e (FIG. 5), which the front face ofthe cutting knife 1 includes with the path 5 along which the block 4 isreciprocated, may be adjusted.

The small tubular member 21 which serves to feed liquid in and out ofthe collecting vessel formed by the plastic strip 2, sealingly connectedat the bottom edge thereof to the rear face of the cutting knife 1,extends with a bent portion thereof over the upper edge of the plasticstrip 2 into the interior of the collecting vessel so that the loweropen end of the tubular member 21 is below the normal level of theliquid in the col lecting vessel. The tubular member 21 is carried bysupport means so that the position thereof with regard to the collectingvessel may be adjusted in substantially vertical and substantiallyhorizontal direction or by turning the support means about its axis asindicated by the arrows in FIG. 5. The support means supporting thetubular member 21 preferably comprise a substantially upright hollowcylindrical member 23 formed in the wall thereof with a pair of oppositelongitudinally extending slots 23a and a solid tubular member 22 in thehollow tubular member 23 and frictionally engaging the inner surfacethereof so as to be shiftable in axial direction and to be held byfriction in any shifted position. The member 22 is formed with a boretransverse to its axis through which the tubular member 21 extends to beshiftable in axial direction while being frictionally held in anyadjusted position. The member 22 may for instance be formed from rubberso as to be slightly compressible. The support means 22, 23 supportingthe tubular member 21 are preferably mounted on the mounting means 19for the cutting knife and removably therefrom in a simple manner. Forthis purpose a pair of cooperating means respectively fixed to the lowerend of the member 23 and to the mounting means 19 may be provided forreleasably attaching the support means, that is the member 23 thereof,to the mounting means 19.

The pair of cooperating means may be constituted, for instance, by apermanent magnet 25 mounted in the lower end portion of the member 23and engaging with the flat bottom face thereofa magnetizable portion ofthe mounting means 19 as shown in FIG. 6.

On the other hand, the pair of cooperating means may comprise a femalesocket member 24a projecting upwardly from the mounting means 19 asshown in FIG. 5, and a male socket member 24 fixed to the lower end ofthe member 23 and projecting downwardly therefrom into the cavity of thefemale socket member 2411, as shown in FIGS. 5 and 7. The male member 24has preferably a cylindrical outer surface so as to be turnable in thesocket member 24a.

The tubular member 21 is connected by a hose or flexible tubing 13 to aliquid supply means which may comprise a rubber ball 26 having an outletend to which the hose 13 is connected, and the rubber ball 26 is looselymounted in the cavity of a cylindrical member 30 which above the cavityin which the rubber ball 26 is located is provided with an axial boreformed with an inner screw thread with which the outer screw thread of aspindle 29 extending through the axial bore of the member 30 isthreadingly engaged. The spindle 29 is likewise formed with an axialbore in which a cylindrical rod 28 is slidably arranged extending withits upper end beyond the upper end of the spindle 29. The rod 28 servesfor quickly filling the interior of the rubber ball 26 with liquid bydetaching the support means 22, 23 from the mounting means of thecutting knife and by dipping the open end of the tubular member 21 in aliquid container after first pressing the rod 28 downwardly into thespindle and thereby compressing the rubber ball 26. After release of therod 28, the rubber ball 26 will resiliently expand so that water will besucked into the interior of the rubber ball. Subsequently thereto, thesupport means 22, 23 are again mounted on the mounting means 19 of thecutting knife 1 and liquid from the rubber ball 26 may be transferredinto the collecting vessel formed by the plastic strip 2 by turning thespindle 29 by means of its upper serrated portion 27 so that liquid istransferred from the interior of the rubberball 26 through the hose l3and the tubular member 21 into the collecting vessel. By turning thespindle subsequently thereto in one or the other direction, the upperlevel of the liquid in the collecting vessel may be very exactlyadjusted. The position of the end portion of the tube 21 can be adjustedso that the end portion in the collecting vessel will be below the levelof the liquid therein and so that the end portion will be out of the wayof the cut sections 6 floating on the liquid in the collecting vessel.Any necessary adjustment can be made in a simple manner by shifting thetube in the bore of the member 22 or by shifting the member 22 in axialdirection within the hollow cylindrical member 23. Whenever an exchangeof the cutting knife 1 is required, the support means 22, 23 for thetubular member 21 may easily be removed from the mounting means of thecutting knife to facilitate exchange of the latter.

The arrangement according to the present invention, especially thearrangement of the tubular member 21 and the support means therefore maybe used in connection with cutting knives of any type and material andwith collecting vessels connected thereto formed by a plastic strip orany other desired material.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofultramicrotomes differing from the types described above.

While the invention has been illustrated and described as embodied in anultramicrotome with means for adjusting the level of the liquid in thecollecting vessel of the microtome, it is not intended to be limited tothe details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range ofequivalence of the followingclaims.

lclaim:

1. In combination with an ultramicrotome having a cutting knife with anupper cutting edge and a collecting vessel fixed to the cutting knife toone side of the cutting edge and adapted to befilled with liquid up tothe cutting edge of the knife for collecting sections cut by theultramicrotome, means for changing the amount of liquid in thecollecting vessel and for adjusting the level of the liquid in saidvessel and comprising a tubular member extending from above into saidvessel and having a lower open end located at an elevation below that ofthe cutting edge of the knife, a remote liquid container of changeablevolume, and tubing connecting said remote container with the other endof said tubular member.

2. The combination as defined in claim 1, and including support meansfor supporting said tubular member adjustable in at least two directionsrelative to said cutting edge.

3. The combination as defined in claim 2, and including mounting meansfor mounting said cutting knife on a support, said support means forsaid tubular member being mounted on said mounting means.

4. The combination as defined in claim 3, wherein said mounting meansare adjustably mounted on said support.

5. The combination as defined in claim 3, wherein said support meansbeing releasably connected to said mounting means.

6.-The combination as defined in claim 3, wherein said support meanshave a lower end and means on said lower end of said support means forreleasably connecting said support means to said mounting means.

7. The combination as defined in claim 3, and including a pair ofcooperating means respectively fixed to said support means and saidmounting means for releasably attaching said support means to saidmounting means.

8. The combination as defined in claim 7, wherein said pair ofcooperating means comprise a female socket member and a male memberreleasably inserted in said female socket member.

9. The combination as defined in claim 8, wherein said female socketmember is fixed to said mounting means and said male member is fixed toa lower end of said support means and frictionally held in said socketmember.

10. The combination as defined in claim 9, wherein said male member isturnably held in said socket member.

11. The combination as defined in claim 7, wherein said pair ofcooperating means comprise a permanent magnet and a portion ofmagnetizable material cooperating with said magnet for releasablyattaching said support means to said mounting means.

' 12. The combination as defined in claim 2, wherein said support meanscomprises a hollow substantially upright cylindrical member formed inopposite wall portions thereof with a pair of elongated slots extendingsubstantially in the direction of the axis of said hollow cylindricalmember, a solid cylindrical member in said hollow cylindrical member andfrictionally engaging the inner surface thereof so as to be adjustablein axial direction, said solid cylindrical member being formed with abore therethrough extending transverse to the axis thereof, said tubularmember extending through said bore adjustable in longitudinal directionand turnable about the axis of the latter.

13. The combination as defined in claim 2, wherein said remote liquidcontainer is resiliently compressible and including means cooperatingwith said compressible liquid container for gradually compressing thesame so as to transfer liquid from said container into said collectingvessel.

